The present invention relates to a device for plug-connection of first and second electric conductors. A plug element has a plug pin associated with the first conductor. A socket element has a socket element associated with the second conductor which receives the plug pin into a pin receptacle to make electric contact.
In conventional plug connection devices, the plug and socket elements must be fastened to the electric conductors associated with them to establish electric contact. As a result, additional contact points arise which present a potential source of malfunction under more difficult operating conditions such as vibrations or aggressive atmospheres. Structural precautions must be taken so that both the plug and the socket elements ensure reliable contact, especially in the area of the contact points. In addition, the socket element is time consuming and costly to manufacture.
DE-GM 1 809 183 discloses a device providing a plug connection between two electrical conductors for low currents in the area of electric information transmission and metrology. The device is connected electrically to connecting conductors by means of the solder connections making up the device, similar to those specified in DE 20 41 065 B2.
U.S. Pat. No. 4,219,252 shows an electric plug connector which forms in the socket area two clamping jaws made up of metal strips. The ends of the metal strips away from the socket are separated in the form of a stirrup to provide electric contact for the socket element.
DE-GM 1 933 165 discloses a one-piece contact spring with two spring halves which are stamped from a metal sheet and then folded together. Electric connection with the connecting conductor is established by a soldered end formed by the contact spring.
DE 79 15 670 U1 describes an electric strip connector with a base area to which at least one finger area, a wire rope coupling, and a connecting element are connected.
U.S. Pat. No. 4,395,081 discloses a plug connector with a socket element designed as a cable lug which may be connected to a grounding plate. For this purpose, the socket element is integral and has two contact prongs directly on the grounding plate.
Objects of the present invention are to provide a device for plug connection of a first electric conductor to a second electric conductor with a plug element associated with the first conductor and a socket element associated with the second conductor. The contact may be established with electric and/or electronic components mounted on a bar and have the smallest possible number of failure-prone contact points, while at the same time ensuring contact protection despite simplicity of manufacture.
The socket element has a metal strip forming the second conductor. The end of the metal strip is shaped and, in particular, is bent transversely to the longitudinal direction of the strip to form the pin receptacle such that the plug pin may be inserted into the plug receptacle in the longitudinal direction of the metal strip. The second conductor and the socket element are designed as one piece. A contact point between the second conductor and the socket element is eliminated. The pin receptacle has, in a cross-section enclosing a right angle with the longitudinal axis of the metal strip, a shape more or less coinciding with the corresponding cross-section of the plug pin. The plug pin is, for example, in the form of a circular cylinder and, like the pin receptacle, designed for a current carrying capacity of 1 to 1000 A, preferably 50 to 200 A. The metal strip is preferably made of copper or a copper alloy, and preferably has a thickness ranging from 0.5 to 2 mm.
As a result of formation of the pin receptacle by bending the metal strip transversely to the longitudinal direction of the strip, the pin receptacle has a high flexural strength, especially in the direction of insertion of the plug pin. The longitudinal direction of the metal strip is more or less parallel to the direction of insertion of the plug pin. The metal strip is, in the area of the pin receptacle, at least partly bent around the central axis of the device. As a result, it is easy to design the socket element as a panel jack mounted on a housing, or integral with the housing or the perforation to be provided for the metal strip or the second conductor.
In the present invention, the metal strip forms a bar outside the socket or plug element, as one piece. On the bar, the components of an electric or electronic appliance are mounted, such as those of an electronic frequency converter for a motor and/or generator appliance. This arrangement eliminates the need for additional contact and connecting points. Reliable operation is achieved with reduced manufacturing and assembly costs. Several metal plates making up a pin receptacle for a socket element per layer may form an overall multilayer bar. The individual layers are electrically insulated from each other. The electric and/or electronic components mounted on the bar may be electrically connected to one or more of the layers, and thus, to one or more of the pin receptacles.
The reliability of contact and the current carrying capacity of the pin receptacle is increased by the socket element having two or more metal strips. The bending radius of the individual metal strips is preferably more or less identical, and in particular smaller than the radius of the plug pin. As a result, the advantage is gained of producing at least two contact points or conductors per metal strip. In addition, the metal strip may have a plurality of punctate conductor or laminar contact points in the area of the pin receptacle which are molded on in one piece and come contact with the plug pin.
Since the at least two metal strips are in one piece, a basically interference-prone electric connecting point is eliminated. As an alternative to the one-piece design of the at least two metal strips, the latter may preferably be mechanically, and optionally also electrically, rigidly connected to each other outside the socket area. Preferably, this connection is bonded, for example, by riveting, soldering, and welding, spot welding in particular, or by flanging of shaped metal tabs. Screw, hook, or catch attachment of the metal strips is also possible, of course. This arrangement permits electrical connection of, for example, two component conductors of the second conductor by the plug connection device. If the connection point of the at least two metal strips provides only a mechanical connection, electrical connection of the at least two metal strips results when the plug element is inserted.
Since the metal strip is or the strips are enclosed in an energy storage fuse element, for example, by one or more clamping rings applying the force of a spring to the metal strips radially, the reliability of contact and current carrying capacity of the pin receptacle are further increased.
Since the pin receptacle is mounted in a preferably electrically insulating socket housing which overlaps the pin receptacle at the end, with an opening left for passage of the plug pin, the socket element is shockproof. The opening for passage of the plug pin is only slightly larger than the plug pin and its shape is adapted to that of the plug pin. The pin receptacle is mounted in the socket element in such a way, and in particular opposite the opening so far, that when a probe is inserted into the opening in accordance with safety regulations, it does not come in contact with the pin receptacle.
Since the socket housing has catch means operating in conjunction with the plug element, the plug connection may be produced by a simple method. In particular it can be made without a special assembly tool. The danger of unintentional contact with the plug pin and/or the pin receptacle is eliminated.
With the plug pin mounted in a plug housing projecting beyond the plug pin in the direction of insertion, a probe does not come in contact with the plug pin when introduced into the plug opening in accordance with safety regulations. In this manner, protection from contact is also guaranteed with respect to the plug element of the plug connecting device. Additional protection from contact is achieved by the plug pin having an electrically insulating end section, preferably produced by means of an electrically insulating sealing element mounted on the end side of the plug pin. Protection from contact is increased and insertion of the plug pin into the pin receptacle is simplified by a sealing element in conical or spherical form on the end side.